Some of them do it because they are paid to do it. Others do it for a mix of dubious motives. Money is one factor. Climate science deniers are predominately right wing extremists who worship the golden calf. They are obsessed with money. For some, greed appears to be their only motivation in life.
Yet that doesn't explain it either. Not logically. Climate change is bad for the economy, meaning that climate science deniers will find it hurts their hip pocket as much as it will hurt the fortunes of normal, rational people.
Part of it is fear. I've noticed that climate science deniers are afraid of being afraid. They use words like "alarmist" to describe people who provide facts. Climate change scares them, as it should.
Another part has roots in authoritarianism. Science deniers typically worship the "scum-bucket politician" as Bob Altermeyer refers to them. That's probably how Donald Trump got elected. Authoritarians wanted to believe his lies. He is, to most people, a blithering buffoon, a reality television fantasy (dark fantasy), a bully, an ignoramus unfit to run a business let alone govern a nation. To right wing authoritarian followers Donald Trump is a saviour who can do no wrong, even though he flips and flops and hasn't kept a single one of the promises he made them.
As an example of the lie promotion, today Anthony Watts posted another article by his replacement, Eric Worrall (archived here). Eric says he wants the USA to get out of the Paris climate agreement. He quotes a lie by Scott Pruitt, who also wants the USA to get out of the Paris climate agreement.
This is the lie: "China and India had no obligations under the agreement until 2030."
That is not true, and if the WUWT science disinformers ever did any some simple fact-checking they would know that. Not that Eric Worrall cares. He gets off on having his name in print on a conspiracy blog. Any fame is better than none, even though it means being associated with the dark side of the internet.
From the Sydney Morning Herald:
Despite our queries, we did not get an explanation for Pruitt's remarks from the EPA, but we have good news for him. If that's his biggest problem, it's solved! His objection is based on a misunderstanding of the agreement: China and India are already hard at work at meeting goals set for 2030.So what did China and India pledge to do in their plans?...Another point is that whether or not the USA ends up pulling out of the Paris agreement (not all that likely), it won't stop global warming. Depending on other actions and inactions in the USA, it will speed it up and make things worse.
...China, in its submission, said that, compared to 2005 levels, it would cut its carbon emissions by 60 to 65 per cent per unit of GDP by 2030. India said it would reduce its emissions per unit of economic output by 33 to 35 per cent below 2005 by 2030.
Note that both countries pledge to reach these goals by 2030, meaning they are taking steps now to meet their commitments. India, for instance, seeks to have renewable power make up 40 per cent of its power base by 2030, so it is investing heavily in solar energy. The country is now on track to become the world's third-largest solar power market in 2018, after China and the United States. China is also investing heavily in renewable energy.
Is that what climate science disinformers want? If so, why? What possible reason could they have for wanting more and worse weather disasters, faster sea level rise, higher costs of adaptation? Is it like arms dealers wanting war? Does Eric Worrall hope to profit from disaster?
From the WUWT comments
There are only four so far and none worth repeating.
References and further reading
Fact Check: EPA chief's Scott Pruitt's claim about China, India and the Paris climate agreement - article by Glenn Kessler at the Sydney Morning Herald, 15 April 2017